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Light Management

Algae breeding and Light Management

2007 the German Professor and Botanist, Dieter Hanelt took of again to Belize to for a research party on board of the small, very small research vessel ALDEBARAN. This was the beginning of a research programme which led him into the waters of China, Svalbard (an island far north of Norway), New Zeeland, the Mediterranean and Belize. One of the tasks was to document the influences of the climate change in the marine environment, the other was about algae.
He was going to prove that these, for the aquatic life, as well as for us humans so important producers of food, which are the very first in the marine food chain, react as sensitive as we humans on direct solar radiation. Extensive solar radiation causes a decrease in photosynthesis with the algae and this can have an influence on the total biocoenosis, which directly or indirectly is depending on algae.
The puzzling result of this research was that the algae species being harmed by solar radiation recovered real fast when the light conditions changed and the UV radiation decreased. The presence of UV-B light quickened the recovery process which implies that a physiological reaction is taking place. Algae species from deeper layers (about 15 m) did not show such effects, but got sunburned instead (shown dark brown spots of dead cell material).

Here we jump...

to a product called LADIVAL (developed in co-operation with Research Institute for environmental medicine in Duesseldorf and the LAVIDAL producer STADA AG).
We are suddenly talking about a Suntan Lotion!
But here`s the solution.
Algae have very different protection mechanism against solar radiation:
Red algae (rhodophyta) are reducing their amounts of their red light collecting proteins, and addition substances similar to melanin are being produced. Melanin (MAA- an amino acid) is a substance also protecting the human skin against the sun.If you have too little of it in your skin - you know what happens....
We people here in the northern part of Europe definately know what could happen - we could get a Melanom - Skin cancer!
Blue algae (Cyanobakteria) primarily living right underneath water surface are protecting themselves by producing an enzyme called Photolyase.
As oxidative damages caused by solar radiation can cause even the death of algae, nature invented the light collecting protein LHCSR3.
Surplus light energy will be transferred into thermal energy and this again produces the enzyme the pharmaceutical industry became so fond of.
Photolyase has the capability to recognize cells damaged by UV-B rays and repair them. The cells of human skin does not have a similar enzyme, but photolyase won from Algae cultures does have the same positive effect also for our skin.

Thus algae became mothers little helper.

Here we jump again, - and back to the arctic cold.

We are again in the waters around Svalbart, Spitzbergen (you remember! ? north of Norway! I have been there myself a couple of times. Fascinating ? but far too cold for a decent living.).
The French-German science group AWIPEV are doing some research, beside others, on the effect of UV radiation on the algae species there. They detected that UV light is reducing the population of brownalgae (phaeophyceae) whereas the spores and germ cells are reacting extremely sensitive upon UV rays. Even UV light in very small dosis will damage the Spores when drifting on the water and thus preventing them to bloom. Other species just dive of, - retreating into deeper waters if the solar radiation increases. Also here there productivity deminish.
I will not go on about the consequences and all the reason that caused all this changes of our environment. We are working all together on something to change this to the better, - don`t we!?

If light is so vitally important for algae as much as too much light is damaging, - just how much light do we need for algae breeding in a PBR system?

And what can we learn from all this?
They need light, off course, but are shy of direct solar radiation. How can we measure how much light? We use a patented Model-Reactor (Pat.Nr. 202007013 401.1) with an LED light source to find out the optimum growth level of algae species. Here we can simulate the light conditions of Germany, Spain, Australia or even India. Also different nutrition requirements can be tested. It has shown for us that here in Central Europe only 10% of solar radiation is necessary to achieve an optimum growth rate. Thus algae cells are converting 5% of the given light into bio energy (something that i.e. the sugar cane can only do with 1% effectiveness). We are able to boost the productivity of algae up to 100 gram per m? per day with this method of finding the right specie. But we even learned more. In a compact algae culture which is mixed up by streaming water, some algae will come into the (light) surface, some will return into the dark. From the view of an algae cell it might appear as if the light is flickering. This Disco-light effect was researched as well. Surprisingly the algae liked it very much! They are able to store the captured light and will use it later, in the dark, for their growth.

I hope I could give some enlightening information(even though it is given in my limited English)to show potential algae breeder how important the factor light is. Since we are growing algae in PBR`s installed in green houses, we had to shade the reactors in summer time even here in Europe to optain an optimum growth rate. We have now Photovoltaic collectors on the roofs of the green houses (partly ? that means roof sides to the south with collectors, other half free) and are very satisfied with this arrangement. For all of these who operate with ponds ? how`s your light management?

Next time I will present our PBR-system.
Thank you for your interest,
Wed March 24 2010 11:09:36 PM by AlgaeNova 1347 views
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